Police official Naeem Khan said least 30 people were also wounded in the attack in the town of Darra Adam Khel in the troubled Khyber Pakhtunkhwa province bordering Afghanistan.

No group immediately claimed responsibility, but Pakistani Taliban militants have staged such attacks in tribal region of Darra Adam Khel to punish elders for backing security forces in offensives against militants in the region.

Darra Adam Khel is famous for its weapons market selling home-made guns crafted by local artisans in this tribal region, where central government is weak. Local elders there have formed "peace committees" to evict militants, and have also helped authorities in the past in operations against insurgents.

It was unclear how many people were present at the office, which belonged to one of the peace committees. Khan said both passers-by and local elders were among the victims.

Provincial Information Minister Mian Iftikhar Hussain condemned the attack, and urged the federal government to consider launching a "decisive operation against terrorists" to eliminate them.

Khan said the dead and wounded were being transported to hospitals in the northwestern city of Peshawar, and some of the injured were listed in critical condition.